If you look at the top row of lettering on the rear cover, without too much imagination, I think you can even see what could possibly, somewhat, maybe, spell out "HOWARD ROTOVATOR". The last word on the top right is likely "Rotovator". The bottom row of lettering is still a mystery, though.
fj40dave, you might take a look under the top deck in either front corner.....some of them had a stamped data plate attached in that location. Seems like an odd place to put one, but they must have had their reasons.
Given your location, that bottom row of lettering could possibly spell out a dealer in MONTANA ?